In a large mixing bowl, combine the melted butter, granulated sugar, brown sugar, and peanut butter. Mix until smooth. Add the coconut milk and vanilla extract, stirring until fully incorporated. Gradually add the flour and salt, mixing until just combined. Finally, fold in the mini chocolate chips.
Line a 9x13 inch baking pan with parchment paper, leaving some overhang for easy removal later. Press the cookie dough mixture evenly into the bottom of the pan, creating a solid base.
Spread the marshmallow fluff evenly over the cookie dough layer, ensuring it covers the entire surface.
Sprinkle the roughly chopped salted peanuts over the marshmallow layer, pressing them gently in to ensure they stick.
In a microwave-safe bowl, combine the caramels and 1/4 cup of coconut milk or cream. Microwave in 30-second intervals, stirring in between, until the mixture is smooth and creamy. Pour the caramel over the peanuts and marshmallow fluff, spreading it evenly.
Sprinkle the pretzels over the caramel layer, pressing them down gently for a nice crunch.
In another microwave-safe bowl, melt the remaining 1 1/2 cups of milk chocolate chips with 2 tablespoons of heavy cream or coconut milk. Stir until smooth and drizzle over the top of the pretzel layer.
Refrigerate the bars for at least 2 hours, or until they are set and firm. Once chilled, lift the bars out of the pan using the parchment overhang and cut into squares.
Serve the bars chilled or at room temperature. Watch as your friends and family devour them!